This is a case of a 21-year-old man who presented with history of abdominal pain following blunt abdominal trauma. Although the initial ultrasound scan showed mild free peritoneal fluid, the patient was managed conservatively as a probable case of splenic injury and was discharged in satisfactory condition after 6 days of admission. He presented again 7 days later with recurring epigastric pain and had exploratory laparotomy on the presumptive diagnosis of peritonitis, probably due to peptic ulcer perforation. Intraoperatively, he was then discovered to have an isolated gallbladder perforation. This is a rare condition in which the diagnosis is often delayed or missed as was the case in our patient. To the best of our knowledge, this is the first reported case of isolated gallbladder perforation in Nigeria, and it behooves the clinician to be aware of the likelihood of this condition in patients with blunt abdominal injury.